Finding the Fourth Proportional to 139,789.81, 192,908.61 and 76,128.67

Step by Step Solution

1. Step 1: Write the proportion equation
   139,789.81 : 192,908.61 = 76,128.67 : x
2. Step 2: Convert to fraction form
   139,789.81/192,908.61 = 76,128.67/x
3. Step 3: Cross multiply
   139,789.81x = 192,908.61 × 76,128.67
4. Step 4: Simplify right side
   139,789.81x = 14,685,875,910.85
5. Step 5: Solve for x
   x = 14,685,875,910.85/139,789.81
6. Step 6: Final answer
   x = 105,056.84